PROJECT SUMMARY Individuals with BRCA1/2 mutation carriers have substantially elevated risk for breast and ovarian cancer, and they can benefit greatly from increased screening and preventive surgeries. Therefore appropriate identification of high risk individuals is an important public health priority and a quintessential example of precision medicine approaches. Widespread efforts have been made by professional organizations and health care systems to encourage providers to screen family histories and offer appropriate referrals for genetic testing and counseling, and there have been substantial marketing efforts directed toward the general public. However, little is known about whether these efforts are increasing the appropriate use of testing among families with greatest risk for having mutation. Current studies looking at the use of genetic testing have relied on chart review, questionnaires or insurance databases which only capture small subsets of patients. This study will addressing these limitations through an unprecedented collaboration between the major healthcare systems across the state, commercial genetic testing laboratories, and the epidemiologic resource of the Utah Population Database (UPDB). Through this study, clinical genetic testing information from the University of Utah, Intermountain Healthcare, the Salt Lake City Veterans Administration, and leading community oncology provider, Utah Cancer Specialists, will be linked to the genealogy, cancer, demographic and socioeconomic information in the UPDB. An estimated 316,000 individuals have been identified in the UPDB as meeting current guidelines for evaluation for hereditary breast/ovarian cancer. By linking these individuals to genetic testing records, we will interrogate many important questions including utilization of genetic testing for hereditary breast/ovarian cancer across the state and across healthcare systems and identifying barriers to appropriate genetic testing in underserved populations. This study is highly generalizable as healthcare systems across the country are addressing the challenges of providing genetic services. Utah's rural and Hispanic populations provide an opportunity to evaluate the use of genetic testing in communities that have not been widely studied. Access to data across healthcare systems is crucial for ensuring meeting national goals for more tailored and efficient healthcare.